Weak/slow WIFI connection - other laptop ok
I have a 13" early-2011 Macbook Pro, that's been sitting on a shelf for two years. Now I have installed an SSD and El Capitan, but I have a very slow WIFI connection. I've tried all of the software solutions to reset the network, wifi, etc. with no effect, and restarted the router, etc. etc.
Below is an image of the connections for two 13" Macbook Pros sitting side-by-side. The bottom, slower laptop has a consistently weaker signal and slower rate regardless of how I place or orient the two laptops in the room.
I've removed the bottom pan and checked the antenna cables and they are tightly connected. Could the problem be the antenna in the display? Or the WIFI module itself?